•What holds protons in the nuclei of
atoms?
–Coulomb (electric) repulsion should make
protons fly apart
•They are packed so close together –
must have very strong force to hold them in
–Nuclear “Strong force” attracts nucleons (protons,
neutrons)
–
•Why doesn’t strong force collapse all
atoms into a giant nucleus?
–Nuclear Strong force is very short range
•falls off quickly after a few proton
radii
–Coulomb force is long range
•falling off only as 1/r2
•
•At large distances only coulomb force is
important Þ
repulsion
•Nuclear Strong Force take over only once
protons pushed close together
–Requires very high speed (high temperature)
collision for fusion
•